Meanwhile, remove casings from sausage if necessary. Cook sausage and onions in large nonstick skillet on medium heat 2 min., stirring occasionally to break up the sausage. Add zucchini; cook and stir 5 to 7 min. or until sausage is done and zucchini is crisp-tender, adding garlic for the last minute. Add cream cheese mixture and tomatoes; cook 3 min. or until heated through, stirring frequently.